Microscope

ABSTRACT

In a microscope, an optical system that includes a zoom lens unit having a straight optical axis is located under a stage portion that carries a sample A thereon. An optical image of the sample A is projected on an image-pickup element via the optical system, and is converted into a picture signal by means of the image-pickup element. The picture signal is delivered to the outside through an external terminal area.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional of U.S. application Ser. No.10/201,067 filed Jul. 22, 2002 now U.S. Pat. No. 6,690,510 which isbased upon and claims the benefit of priority from the prior JapanesePatent Application No. 2001-223480, filed Jul. 24, 2001, the entirecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a microscope, and more particularly, toa microscope for converting an observed image of a specimen, such ascellular tissue or a microorganism, into a picture signal to beobserved.

2. Description of the Related Art

Computers are utilized in the field of education nowadays. Computerizededucation is expected to cover various courses of study that utilizeactual computers, as well as simple computer training.

In science education, for example, cellular tissue, microorganisms, etc.are directly observed with use of microscopes, and besides, theirobserved images are supposed to be converted into picture signals, whichare to be observed on computers.

A conventional microscope that can generate those picture signals isdescribed in Jpn. Pat. Appln. KOKAI Publication No. Publication No.10-333055. In this microscope, a lens unit is located next to a specimenstage portion, and a CCD unit is situated on a bent optical path thatextends from the lens unit. In acquiring a picture signal, a specimen orsample is placed on the specimen stage portion, and the stage portion isrotated to adjust the focus. Thereafter, an optical image of thespecimen is formed by means of the lens unit. The optical image formedin this manner is guided through the bent optical path to a CCDimage-pickup element of the CCD unit and converted into electricinformation, whereupon a picture signal is generated.

In the microscope described above, however, the optical image that isfetched by means of the lens unit is guided to the CCD image-pickupelement through the bent optical path. Therefore, the microscoperequires use of a lot of essential optical parts, so that itsconstruction is complicated and its optical performance is not veryhigh.

According to this conventional microscope, moreover, the focus isadjusted by rotating the specimen stage portion, so that the directionand position of the specimen on the stage portion inevitably shiftsduring the focus adjustment. Accordingly, its imaging range or pictureframe is unstable, so that the microscope is not easy to handle. It isvery hard for this microscope, in particular, to acquire picture data ofspecimens or sample that have directional shapes, among other specimensor sample including cellular tissue and microorganisms that are observedin educational scenes.

As described above, the conventional microscope has a slim opticalstructure such that the optical image is guided to the CCD image-pickupelement through the bent optical path. Thus, the optical path is socomplicated that the optical performance of the microscope is poor.

BRIEF SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a microscopefor observing a sample to output an electrical image informationrelating to an image of the sample, comprising:

-   -   a stage portion configured to permit the sample to be mounted;    -   an image-pickup element, on which an optical image of the sample        is formed, configure to convert the optical image into the        electric image information,    -   an optical system, having the optical axis extending in a        straight line between the stage portion and the image-pickup        element, configured to guide the optical image of the sample to        the image-pickup element;    -   a light source unit including one light source configured to        emit an illumination light beam for illuminating the sample and        a mechanism configured to alternatively locate the light source        in any of first, second, and third irradiative positions for        transmissive illumination, incident illumination, and oblique        illumination, thereby selecting one of the transmissive        illumination, incident illumination, and oblique illumination.

According to an another aspect of the invention, there is provided amicroscope for observing a sample to output an electrical imageinformation relating to an image of the sample, comprising:

-   -   a stage portion configured to permit the sample to be mounted;    -   an image-pickup element, on which an optical image of the sample        is formed, configured to convert the optical image into the        electric image information,    -   an optical system, having the optical axis extending in a        straight line between the stage portion and the image-pickup        element, configured to guide the optical image of the sample to        the image-pickup element;    -   an optical lens barrel portion, the image-pickup element and the        optical system being arranged the optical lens barrel portion;        and    -   a stage moving mechanism configured to support the stage portion        on the optical lens barrel portion and move the stage within a        plane substantially perpendicular to the optical axis.

According to an another aspect of the invention, there is provided amicroscope for observing a sample to output an electrical imageinformation relating to an image of the sample, comprising:

-   -   a stage portion configured to permit the sample to be mounted;    -   an optical system, located under the stage portion and including        a zoom lens unit, configured to form the optical image of the        sample;    -   an image-pickup element, which is arranged in the image forming        position of the optical system for the sample and on which the        optical image is formed, configured to convert the optical image        into the electric image information,    -   an external output portion configured to convert the electric        image information generated from the image-pickup element into a        picture signal and delivering the signal to the outside of the        microscope;    -   a base portion configured to hold the image-pickup element and        the external output portion;    -   a support structure configured to support the stage portion on        the base portion and also support the optical system;    -   a zoom control portion, located between the base portion and the        stage portion, configured to move the zoom lens unit along the        optical axis; and    -   a focus adjusting mechanism, supported under the stage portion        by means of the support structure, configured to focus the        optical system on the sample.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention, and together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIG. 1 is a perspective view schematically showing the externalappearance of a microscope according to an embodiment of the invention;

FIG. 2 is a schematic sectional view taken along the optical axis of themicroscope of FIG. 1;

FIG. 3 is a cutaway plan view schematically showing a part of a stageplate in order to illustrate the construction of the stage plate;

FIGS. 4A and 4B are perspective views schematically showing lens framesof a zoom lens unit shown in FIG. 1;

FIG. 5 is a development showing cam grooves formed on a turn ring inorder to urge the lens frames shown in FIGS. 4A and 4B to move in thedirection of the optical axis;

FIG. 6 is a perspective view schematically showing a mode of use of themicroscope shown in FIG. 1;

FIG. 7 is a partial sectional view schematically showing a part of amicroscope according to another embodiment of the invention;

FIG. 8 is a sectional view schematically showing a microscope accordingto still another embodiment of the invention;

FIG. 9 is a sectional view schematically showing a microscope accordingto a further embodiment of the invention;

FIG. 10 is a sectional view schematically showing the microscope of FIG.9 and illustrating the way a lighting system of the microscope is used;

FIG. 11 is an enlarged plan view schematically showing a part of themicroscope shown in FIG. 9; and

FIG. 12 is a partial sectional view schematically showing a part of amicroscope shown in FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

A microscope according to an embodiment of the present invention willnow be described in detail with reference to the accompanying drawings.

FIGS. 1 and 2 show the microscope according to the embodiment of theinvention. FIG. 1 shows the external appearance of the microscope, andFIG. 2 shows a profile along the optical axis of the microscope.

As shown in FIG. 1, the microscope is in the form of a cylinder having abase portion 6 at the bottom and a stage portion 2 at the top. Forexample, the microscope is 187 mm high, and the base portion has anoutside diameter of 124 to 150 mm.

As shown in FIG. 2, the microscope comprises the stage portion 2 thatcarries a sample A thereon, a zoom lens unit 3 as an optical systemcapable of focusing and changing the magnification of an optical imageof the sample A on the stage portion 2, and an image-pickup portion 4that includes an image-pickup element for detecting the optical imageenlarged by means of the zoom lens unit 3. All these portions aremounted on the base portion 6 so as to their respective optical axes aresubstantially on a straight line. The optical image is applied theimage-pickup portion 4 through the zoom lens unit 3 and the image-pickupportion 4 converts the input optical image into electric imageinformation and processes it to generate a picture signal. This picturesignal is externally delivered to an external apparatus, such as apersonal computer 20, through an external terminal unit 5 such as auniversal serial bus, which is so called USB. Thereupon, a picture of anobject of observation is displayed on a display device 30 which isconnected to the personal computer 20.

The stage portion 2 is provided with a stage plate 201 that has anopening 201 a near its optical axis. As shown in FIG. 3, a pair ofcontrol knobs 203 and 204 are screwed into the outer peripheral surfaceof the stage plate 201 for sliding motion in a direction substantiallyperpendicular to the optical axis. They are spaced at about 90° inrespect to the optical axis of the microscope. A plunger 205 is opposedto the control knobs 203 and 204 so as to be slidable in the samedirection. The plunger 205 is pressed in a direction perpendicular tothe optical axis by means of a spring 205 a and a stopper screw 205 b.

The control knobs 203 and 204 and the plunger 205 have spherical orrounded distal ends, respectively. A stage support base 202 is providedwith a ring section having an outer peripheral surface on which recesses202 b are formed. Each of the recesses 202 b has a inclined face forreceiving a corresponding one of the distal ends of the control knobs203 and 204 and the plunger 205. The spherical distal ends of thecontrol knobs 203 and 204 and the plunger 205 are contacted to the faceof the recesses 202 b formed on the outer peripheral surface of thestage support base 202. Each of the recesses 202 b is formed as acircular corn space and has a part of the face inclined to the specimenor sample A and extended as to face the specimen or sample A. As thedistal ends of the control knobs 203 and 204 is pressed to the inclinedface of the recess 202 b, a pressing force is produced between the facesand the distal ends of the control knobs 203 and 204 and the pressingforce is applied to the control knobs 203 and 204 in a direction awayfrom the specimen A.

Thus, the pressing force is applied to not only the control knobs 203and 204 but also the stage plate 201 in the direction of the stagesupport base 202, i.e., in the direction away from the specimen A.Accordingly, a lower surface 201 b of the stage plate 201 is pressedagainst an upper surface 202 a of the stage support base 202, wherebythe stage plate 201 can be mounted on the stage support base 202 withoutplay. When the control knobs 203 and 204 are rotated, so-called framingis executed such that they control the stage plate 201 for an orthogonalmovement in the horizontal direction and a rotational movement inconjunction with the plunger 205, thereby setting the stage plate 201 ina desired position on the stage support base 202.

The stage support base 202 may have an inclined outer peripheralsurface, instead of the recess 202 b formed on the outer peripheralsurface of a stage support base 202. The respective distal ends of thecontrol knobs 203 and 204 and the plunger 205 are so contacted andengaged on the inclined outer peripheral surface as to apply a contactpressure to the inclined outer peripheral surface in a direction awayfrom the stage plate 201 and urge the stage plate 201 to be contacted onthe stage support base 202.

The zoom lens unit 3 includes first, second, third, fourth, lenses 301,302, 303, 304 and 305, which are arranged so that their optical axis Bextends in a straight line. The first lens 301 is formed of an auxiliarylens called a conversion lens, and is fixed to a lens frame 306 by meansof a ring spring 307. The lens frame 306 is slidably fitted in a fittingportion 202 c that is situated near the optical axis of the stagesupport base 202.

Further, a groove 306 a is formed on the outer periphery of the lensframe 306. An eccentric pin 206 a of a focusing handle 206 that isrotatably attached to a side hole 202 d of the stage support base 202 isfitted in the groove 306 a.

In addition, the eccentric pin 206 a is eccentrically positioned fromthe rotating center of the focusing handle 206. A stopper pin fixed inthe support base 202 is engaged with the focusing handle 206 so that thehandle 206 is prevented from being dropped out from the support base.Thus, the handle 206 is rotatably held in the support base 202 by meansof a spring washer 208 and washer 209 which apply a moderate force tothe handle 206.

As the handle 206 is so operated as to rotate, the eccentric pin 206 ais rotated around the center of the handle 206 with a radius of theeccentric distance between the centers of the handle and the eccentricpin 206 a. Accordingly, the first lens 301 can be moved in the directionof its optical axis to bring the sample A into focus.

The second lens 302 is fixed in the fitting portion 202 c of the stagesupport base 202 by means of the ring spring 308. The third lens 303 isfixedly bonded on a lens frame 309 that has a fitting hole 309 a and afitting slit 309 b shown in FIG. 4A. The fitting hole 309 a and thefitting slit 309 b of the lens frame 309 are fitted individually on twosupport posts 602 for use as support members for axial movement alongthe optical axis. Further, the fourth lens 304 is fixedly bonded on alens frame 310 that has a fitting hole 310 a and a fitting slit 310 bshown in FIG. 4B. The fitting hole 310 a and the fitting slit 310 b ofthe lens frame 310, like those of the lens frame 309, are fittedindividually on the two support posts 602 for axial movement along theoptical axis.

The two support posts 602 are fixed in a manner such that they arearranged between the stage support base 202 and a base 601 of the baseportion 6. The support posts 602 are surrounded by a turn ring 603 thathas cam grooves 603 a and 603 b in its inner wall, as shown in FIG. 5 asdescribed later. As shown in FIG. 2, the upper and lower end faces ofthe turn ring 603 is held between the stage support base 202 and thebase 601 with narrow gaps between them. The top and bottom portions ofthe turn ring 603 are rotatably fitted on cylindrical protrusions of thestage support base 202 and the base 601, respectively.

A cam follower 309 c on the lens frame 309 and a cam follower 310 c onthe lens frame 310 are fitted in the cam grooves 603 a and 603 b of theturn ring 603, respectively. As shown in the development of FIG. 5, forexample, the cam grooves 603 a and 603 b are formed having a desiredshape such that the image of the sample A can be enlarged and reduced insize by means of the third and fourth lenses 303 and 304 as it is formedon the respective focal points of the lenses.

Thus, when the turn ring 603 is so operated as to rotate, the camfollowers 309 c and 310 c are guided on the cam grooves 603 a and 603 b,respectively, to move the third an fourth lenses 303 and 304 (indicatedby two-dot chain lines in FIG. 2), thereby enlarging and reducing theoptical image of the sample A.

The fifth lens 305 is fixedly fitted in the base 601 by means of a ringspring 604.

Further, the image-pickup portion 4 includes an image-pickup element401, which receives the optical image of the sample A enlarged by meansof the zoom lens unit 3 and converts it into electric information, and acircuit board 402 for holding the image-pickup element 401. The circuitboard 402 is fixed on the base 601 of the base portion 6 in a mannersuch that the image-sensing surface of the image-pickup element 401 thatis formed integrally with the board 402 is in line with the opticalfocal point (image forming point) of the zoom lens unit 3.

Furthermore, the external terminal area 5 includes a processor 501formed integrally on the circuit board 402 and a terminal 503 such as aUSB to be connected with the personal computer 20. The processor 501processes the electric information from the image-pickup element 401 andconverts it into a picture signal that can be outputted externally. Theprocessor 501 and the terminal 503 are connected electrically to eachother by means of a lead wire 502, and are configured to be able tooutput the picture signal externally or be supplied with power from thepersonal computer. Thus, the image-pickup portion 4 is supplied withpower from the personal computer that is connected to the externalterminal area 5 as its drive is controlled. In consequence, the numberof parts used in the microscope can be reduced, so that the microscopecan be simplified in construction and reduced in size.

In observing the sample A in this arrangement, the personal computer isfirst connected to the external terminal area 5. If this is done, theimage-pickup portion 4 is supplied with power from the personalcomputer, and the turn ring 603 is operated to rotate. Thereupon, thecam followers 309 c and 310 c of the lens frames 309 and 310 of thethird and fourth lenses 303 and 304 are guided by the grooves 603 a and603 b of the turn ring 603, as mentioned before, so that the movement ofthe zoom lens unit 3 in the direction of the optical axis is adjusted,and the magnification of the formed optical image is settled.

As this is done, the control knobs 203 and 204 are rotated to adjust themovement of the stage plate 201 and frame the sample A in a desiredposition. At the same time, the rotation of the focusing handle 206 isadjusted to regulate the movement of the first lens 301 in the directionof the optical axis, thereby bringing the sample A into focus.

The optical image of the sample A placed on the stage plate 201 isenlarged by means of the zoom lens unit 3, and is formed and convertedinto electric information by means of the image-pickup element 401 ofthe image-pickup portion 4. The electric information is processed togenerate a picture signal. This picture signal is delivered to thepersonal computer 20 through the external terminal area 5. As this isdone, the image-pickup portion 4 is supplied with power from thepersonal computer through the external terminal area 5, as mentionedbefore, whereby its operation is controlled.

According to this arrangement, the image-pickup element 401 is opposedstraight to the underside of the stage portion 2 across the zoom lensunit 3 that has a straight optical axis. The picture signal is generatedfrom the electric information converted by means of the image-pickupelement 401 and outputted externally. Accordingly, the optical path issimplified, and miniaturization and simplification of construction canbe realized without failing to maintain high-efficiency opticalperformance. Thus, the ease of handling of the microscope, including itsportability, can be improved. According to this arrangement, moreover, apicture signal for an optical image with a seamless magnification can beacquired with ease.

According to this arrangement, furthermore, the microscope is theso-called inverted microscope in which the zoom lens unit 3 is locatedon the backside of the stage plate 201 of the stage portion 2 on top ofwhich the sample A is placed. Therefore, the sample A to be observed isnot limited in size, and may be any substance that can be placed on thestage plate 201 of the stage portion 2. Thus, a wide variety of objectscan be observed. As shown in FIG. 6, for example, a user 100 can observethe surface of a bulky object, such as the bark of a tree 100, in amanner such that he/she holds the turn ring 603 and applies the stageplate 201 of the stage portion 2 to the tree.

According to this arrangement, moreover, the sample A can be broughtinto focus by adjusting the movement of the first lens 301 of the zoomlens unit 3 with the stage plate 201 fixed. Thus, high-accuracy focusadjustment can be effected by simply rotating the focusing handle 206,and the sample A on the stage plate 201 can be framed by only rotatingthe control knobs 203 and 204 to adjust the movement of the stage plate201 on a flat surface.

According to the embodiment described above, furthermore, the first lens301 of the zoom lens unit 3 is provided as focus adjusting mechanism formovement in the direction of the optical axis. Alternatively, however,the focus adjusting mechanism may be arranged in the manners shown inFIGS. 7 and 8. In FIGS. 1 to 5 and FIGS. 7 and 8, like numerals are usedto designate like portions, and a detailed description of those portionsis omitted.

In the arrangement shown in FIG. 7, the fifth lens 305 is located formovement in the direction of the optical axis with respect to the base601, and its movement in the direction of the optical axis can beregulated for focus adjustment. More specifically, the fifth lens 305 isattached to a lens frame 305 a by means of the ring spring 604, and thelens frame is mounted on the base 601 for movement in the direction ofthe optical axis. A driven groove 305 b is formed around the lens frame305 a, and the eccentric pin 206 a on the focusing handle 206 can beinserted into the groove 305 b. The handle 206 is rotatably mounted onthe base 601 by means of the stopper pin 207, spring washer 208, andwasher 209. As the handle 206 is rotated, the lens frame 305 a of thefifth lens 305 can be moved in the direction of the optical axis bymeans of the eccentric pin 206 a to adjust the focus of the zoom lensunit 3.

According to this arrangement, the focus can be adjusted near the baseportion 6, so that the user 100 can operate the microscope with his/herhand on a desk. Thus, stable adjustment operation can be realized.

Focus adjusting mechanism capable of adjusting the focus by moving thefifth lens 305 in the direction of the optical axis can be combined withthe foregoing focus adjusting mechanism that uses the first lens 301. Bydoing this, the range of focus adjustment can be widened, and the modeof observation can be diversified. If the first and fifth lenses 301 and305 are differentiated in optical power, in this case, the focusingeffect of the first lens 301 compared with its movement can be madedifferent from the focusing effect of the fifth lens 305. Thus, rough-or fine-movement focusing operation can be carried out by operatingthese lenses separately.

In the arrangement shown in FIG. 8, moreover, the overall length of theturn ring 603 is made shorter than that of each support post 602 so thatthere are gaps a and b between the ring 603 and the base 601 and betweenthe ring 603 and the stage support base 202, respectively. According tothis arrangement, the turn ring 603 doubles as a control portion for theenlargement and reduction of the image of the sample A and as a controlportion for bringing the sample A into focus. Accordingly, theoperations for focusing and for the enlargement and reduction of thesample image can be carried out by manipulating only one part. Thus, thehandling operation can be simplified, and the number of essential partscan be reduced.

According to this embodiment, moreover, the turn ring 603 can be movedin the direction of the optical axis by means of an eccentric pin or anyother control means without being directly operated, as in the case ofthe operation for moving the first lens 301 of the foregoing embodiment.By doing this, defocus during the operation for the enlargement andreduction of the sample image can be reduced, and additional effects canbe expected.

The present invention is not limited to the embodiments described above.A light source unit 8 may be provided on the stage base portion 2 shownin FIGS. 9 to 11, which corresponds to the stage base portion 2 shown inFIG. 2. In FIGS. 1 to 5 and FIGS. 9 to 11, like numerals are used todesignate like portions, and a detailed description of those portions isomitted.

The light source unit 8 includes a light source 801 and a power supplycontroller 802 such as a variable resistor, for power supply control,which are mounted on a base plate 804. The controller 802 is connectedelectrically to the image-pickup portion 4 or circuit board 402 by meansof a cable 803.

A cylindrical part 806 is located around the light source 801. Acondenser lens 807 is attached to the cylindrical part 806 by means of aring spring 805. The lens 807 is used to focus light from the lightsource 801 on the sample A that is placed on the stage portion 2. Thebase plate 804 and the cylindrical part 806 are fixedly supported on oneend portion of an arm 809. The other end portion of the arm 809 isattached to a stage support base 210 by means of a fixing knob 808 sothat its angle around the axis of the knob 808 is adjustable. The baseplate 804 and the cylindrical part 806 that are supported by means ofthe arm 809 are enveloped in a sheathing cover 810, which is indicatedby two-dot chain line in FIG. 9, for example. A part of the cylindricalpart 806 projects outside the sheathing cover 810 in order to irradiatethe stage plate 201 with the light from the condenser lens 807.

A hole 210 a is formed in the side face of the stage support base 210.Illumination light from the light source unit 8 is applied to the sampleA through the hole 210 a from under the stage plate 201 as the arm 809is rocked around its axis.

If the personal computer 20 shown in FIG. 2 is connected to the terminal503 of the external terminal area 5 in this arrangement, electric powerthat is supplied from the personal computer is supplied to the lightsource unit 8 through the image-pickup portion 4, whereupon the sample Aon the stage plate 201 is illuminated by transmission. As this is done,the supplied power can be adjusted by operating the controller 802, sothat an image with steadier brightness and color can be obtained.

If the arm 809 is tilted with the fixing knob 808 loosened, moreover,oblique transmissive illumination can be effected by means of the lightsource unit 8. Incident illumination or oblique incident illuminationthrough the hole 210 a of the stage support base 210 can be realized byadjusting the tilt angle of the light source unit 8 in a manner suchthat the source unit 8 is tilted so as to face the hole 210 a, asindicated by two-dot chain line in FIG. 10, for example.

According to this embodiment, the light source unit 8 can apply steadierillumination light to the sample A, so that a bright, high-resolutionimage can be obtained, and high-accuracy observation can be facilitated.Further, the observation mode can be switched betweentransmissive-illumination observation, incident-illuminationobservation, and oblique-illumination observation by simply rocking thearm 809 around its axis. Thus, various observation methods can berealized with ease. According to this arrangement, furthermore, electricpower from the personal computer 20 is supplied to the light source unit8 through the circuit board 402, so that the number of essential partscan be reduced, and therefore, the microscope can be miniaturized.

The light source unit 8 can be easily adjusted to different illuminationmodes by attaching the arm 809 to the stage support base 210 in themanner showing 11, for example. More specifically, the stage supportbase 210 is provided with a protuberance 210 c that has an angledreference surface 210 b for arm attachment. The arm 809 is provided withtwo surfaces 809 a and 809 b that are inclined at given angles,corresponding to the reference surface 210 b of the protuberance 210 c.

In this arrangement, the light source unit 8 can be accurately locatedin a predetermined position suited for transmissive illumination byfixing the arm 809 by means of the fixing knob 808 with the surface 809a of the arm 809 held against the reference surface 210 b of theprotuberance 210 c of the stage support base 210. Thus, transmissiveillumination is executed (see FIG. 10). Then, the fixing knob 808 isloosened, and the arm 809 is lifted above the protuberance 210 c androtated. In this state, the arm 809 is fixed by means of the fixing knob808 with the surface 809 b held against the reference surface 210 b ofthe protuberance 210 c this time. The light source unit 8 is positionedfor incident illumination, facing the hole 210 a of the stage supportbase 210, as indicated by two-dot chain line in FIG. 10, and incidentillumination is executed.

Thus, illumination in a predetermined position can be easily repeated byusing the single light source unit 8. For example, a desired state ofillumination, such as a state with the best optical performance or abright state, can be easily reproduced, so that the ease of handling ofthe microscope can be improved.

The fixing knob 808 is rotatably mounted on the protuberance 210 c ofthe stage support base 210 with its central axis C or axis of rotationdeviated from the optical axis B for a distance X corresponding to thehole 210 a. Thus, by only variably setting the distance X of the lightsource unit 8, ranges of illumination for a light beam D fortransmissive observation and a light beam E for incident observation canbe set with ease, as shown in FIG. 10, for example.

In each of the embodiments described above, the stage plate 201 thatconstitutes the stage portion 2 is mounted on the stage support base 202(210) by means of the control knobs 203 and 204 and the plunger 205 in amanner such that it can move and rotate on a plane substantialperpendicular to the optical axis of. Alternatively, however, the stageportion may be of a so-called grinding-stage structure such that thestage plate 201 is mounted on the stage support base 202 (210) with useof pasty oil, such as grease, for movement and rotation on a planesubstantially perpendicular to the optical axis. According to thisarrangement, the stage plate 201 can be framed more easily.

In the embodiment described above, the microscope has the configurationwherein the stage plate 201 constituting the stage portion 2 is mountedon the stage support base 202 by means of the control knobs 203, 204 andthe plunger 205 in such a manner that the stage plate 201 is controlledto be moved and rotated on the plane perpendicular to the optical axisof the optical system. However, in this invention, it is not limited tothat configuration and a modified configuration can be applied to thestage structure. In an example of the modified configuration, the stageportion has a gliding stage structure in which the control knobs 203,204 and the plunger 205 are removed from the configuration shown in FIG.2, and a pasty oil such as a grease is applied between the stage plate201 and the stage base 202 to allow the stage plate to be moved androtated on the plane perpendicular to the optical axis of the opticalsystem.

This stage configuration can realize a easy to handle the stage plate201 and a simple operation of the framing with utilizing the stage plate201.

According to the embodiment described above, moreover, the two supportposts 602 are used as support members to couple the stage support base202 to the base 601. Alternatively, however, three or more support posts602 may be used to couple the stage support base 202 (210) and the base601.

According to the embodiment described above, furthermore, the controller802, i.e., the variable resistor, for controlling and adjusting theelectrical power supply is mounted on the light source 801. However, itis not limited that the controller 802 is mounted on the light source.Alternatively, the controller 802 may be mounted on the circuit board402, which is provided in the base 601 of the base portion 6, and anoperating part 802 b of the controller 802 is so provided as to projectfrom the base 601 along the turn ring 603. In this arrangement, it iseasy to handle the magnification adjustment of the zoom lenses and thelight intensity control of operating the power supply adjustment,because the operating part of the controller 802 is located in thevicinity of the turn ring 603.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. A microscope for observing a sample, comprising: a stage portionhaving a stage surface configured to permit the sample to be contacted;an image-pickup element arranged at an opposite side of the stagesurface to receive an image of the object, and configured to convert animage of object into an electrical signal: an optical system, having theoptical axis extending in a straight line between the stage portion andthe image-pickup element, configured to guide the optical image of thesample to the image-pickup element; a light source unit including onelight source configured to emit illumination light rays for illuminatingthe sample and a mechanism configured to alternatively locate the lightsource in any of first, second, and third irradiative positions fortransmissive illumination, incident illumination, and obliqueillumination, thereby selecting one of the transmissive illumination,incident illumination, and oblique illumination.
 2. A microscopeaccording to claim 1, wherein the optical system includes a zoom lensunit, and the microscope further comprises a base portion, a pluralityof support members supporting the stage portion on the base portion, alens frame supporting the zoom lens unit on the support members, and alens frame moving mechanism configured to move the lens frame along theoptical axis.
 3. A microscope according to claim 2, which furthercomprises a hollow rotating cylinder portion rotatably attached to thebase portion and the stage portion, and wherein the optical system isreceived in the rotating cylinder portion, and the lens frame movingmechanism is actuated to move the lens frame along the optical axis asthe rotating cylinder portion is rotated.
 4. A microscope according toclaim 1, wherein the optical system includes a lens for adjusting thefocus of the optical system, and the microscope further comprises afine-movement mechanism configured to finely move the focus adjustinglens in the direction of the optical axis, thereby focusing the opticalsystem on the sample.
 5. A microscope according to claim 1, wherein thelight source unit includes an arm member configured to support the lightsource, which is attached to the stage portion for adjustable rotation,and the light source is alternatively located in one of the first,second, and third irradiative position as the arm member is rotated.